BodyMedia FIT review: data, data, and more data for exercisers

There are lots of gadgets targeted towards fitness freaks, but there aren't …

Exactly how many calories do you burn in a day? For the health-conscious (or just data-obsessed), this isn't as easy a question to answer as it seems. There are millions of calorie burn calculators out there, but they are all estimations. Do you work entirely seated during the day, or semi-seated? Are your walks to and from lunch fast enough to count as "brisk," or are they really just strolls? How hard are you really working when you run? The estimates might come close, but they vary so wildly that it's hard to really know what to believe. Do I really burn 1,750 calories just by my body existing for a day, and 2,500 calories by actually being awake and doing stuff?

These are the types of questions that sparked the development of a new type of fitness gadget—the kind that latches onto your body in an attempt to measure your real calorie burn. These devices do this by measuring your body temperature, the rate at which heat is leaving your body, sweat levels, pulse, and body motion, among other things.

The most famous of these is the BodyBugg, used on the popular weight loss show The Biggest Loser, but there are others just like it—in particular, the BodyMedia FIT, which is essentially the same product as the BodyBugg but under different branding. (In fact, a BodyMedia spokesperson confirmed to us that BodyBugg is actually owned and developed by BodyMedia.) We were given the opportunity to try out a BodyMedia unit, and found that it gave us all the data we ever wanted to know, and then some.

What you get and how you use it

The standard BodyMedia FIT "package" is the armband for $190, plus the online activity manager that requires a monthly subscription (this ranges from $7 per month if you pay for 12 months at a time, up to $13 per month on a month-to-month basis). There's also the armband plus a wireless display, which is a little device that shows you in real time what your armband is reading—these two things cost $260 together, plus the same online activity manager subscription fees. We were given review units for the armband and display:

The "armband" portion is actually a USB-capable device that is locked into a stretchy band that goes around your arm. The unit itself can pop out of its holder so you can plug it into your computer via USB to sync with the activity manager on either a Mac or Windows machine. BodyMedia claims that it can monitor 9,000 different elements of your body in order to come up with a calorie burn estimate, as well as a number of other metrics.

As mentioned above, the separate display unit only serves to show you the data that your armband is collecting and whether or not you have met your goals for the day—the system does not require the use of the display if you don't want to pay extra for it, but we found it very useful when measuring the calorie burn of specific activities.

When you're being tracked by the armband, the display can show you things like your total calorie burn for the day so far, your total from yesterday, and the number of steps you have taken so far today, There's also a "trip" mode, which works sort of like a trip meter on your car that allows you to reset the number of miles for a specific trip—when you reset the trip mode on your display, it will go to zero (calories, steps, etc.) and allow you to see how many calories you burn from the time you reset it.

The armband is meant to strap to your arm for every waking and sleeping moment of the day—the only time you shouldn't wear it is when you're in the shower or swimming, as the device isn't waterproof. It isn't terribly bulky and can easily hide underneath a shirt with loose sleeves. The device straps to your tricep area, and the left arm is recommended, although you could use either arm. Since it can also measure your sleep cycle, you're supposed to wear it while sleeping too, although if you're a side-sleeper, you may find yourself feeling a little like the Princess and the Pea if the unit is strapped to your preferred sleeping side.

The "relations" result is pretty humorous. I rarely sweat simply sitting at my desk, nor do I ever get out of breath. I would expect to burn considerably more calories than mostly passive clicking or typing. The real issue, though, is accuracy. First you have the user error aspect, for less precise calorie counters, then you have the uncertainty of the device itself. I haven't watched The Biggest Loser, so maybe that's sufficiently verified real world usage.

I like the idea of this, but being tied to a paid cloud service makes me squeamish about the commitment.

If it can xml/csv export or something then making the plunge on purchase price might be doable. Then you can try upsell me to the service if its better than what I can knock up myself. The bundle makes me run. (away from it, not as in it makes me start exercising )

I think I'm going to have to get this someday. I play tennis and I just can't accept the general blanket figures given for calorie burn. Even the ones that are discerning enough to separate doubles from singles (my estimation is that doubles is only about 1/4 as intense as singles), different opponents will cause significant variations in the amount of effort I apply. The times my opponents spend between points and between games can affect how much work I am doing in a given time period.

Thank you for this article. I always find these kinds of in-depth gadget reviews of both mainstream and "fringe" products to be incredibly valuable when they come from Ars. Despite having no interest in this product, the article was a great read and I look forward to many more like it. Thanks again!

Those calorie estimates seem way off for running, by about a factor of two based on your distances. The accepted burn rate is about 100 calories per mile, regardless of speed. The unit must be counting the workout + basal rate to give you a total. In order to get the true calorie burn of the workout, you would need to subtract your basal rate for the duration of the run.

I agree that the running-burn rates are including your basal rates. That means it's not telling you how much *extra* you burn for running, say, a mile, but rather telling you how much you burn by living *and* running a mile. The other calorie calculators are telling you just the latter. Hence the discrepancy.

I should say: it's also well-accepted that what's necessary to figure out how many calories you burn in a day is only to figure out how much goes in (weigh, measure your food) and then weigh oneself. After a few weeks, you'll get a statistically significant trend in weight that can then be evaluated in terms of the 3500c=1lb formula. It's hard to imagine that this device does any better.

I have a friend who has been very happy with the Body Bugg. I don't think the accuracy matters as much as the relative values. You want to know what burns more or less calories, or just how active your day was, and these devices are great for that.

If this is the same device I looked at before, it doesn't even do heart rate monitoring... as pancakesandbeyond says, it would be nice to get a idea of how it works.

The usefulness is easy to see, but as others have said, the price + a subscription fee (seriously?) = no. If you run, walk, hike a Forerunner GPS watch makes so much more sense if you need to buy something.

(Since it was available to be analyzed, certain "adult" activities for 30 minutes ran me about 65 calories according to BodyMedia, whereas FitDay put that estimate closer to 53 calories. Even if you go by the higher number provided by BodyMedia, it's still only barely above what I burn per hour just sitting at my desk all day.)

Was the adult activity solo or accompanied? I would bet, depending on the "position", that accompanied has the potential to burn quite a bit more or less.

I really wish technology would go much faster. All I use right now is just a HRM watch with chest strap(iphone gps doesn't get crap in Iraq). I want a watch that does HRM, GPS, calories, body temp and what ever else they can cram in it

"The second question is a little harder: is the device itself worth the money? $260 for the FIT unit and the display is a little steep, and many people probably wouldn't drop that kind of cash just to find out that they only burn 65 calories while having "relations.""

Seems to me there is plenty of scope here for some entrepreneur to rent this things out for a month, or even a week. Really, all most people care about is to use the thing for a week, get a feel for how many calories are spent doing what, at which point they are done. Certainly I wouldn't buy one at that price (especially given the gratuitous pissing over mac users) but I'd be willing to rent one for a week at maybe $20 to see what it has to say that I don't already know.

(Since it was available to be analyzed, certain "adult" activities for 30 minutes ran me about 65 calories according to BodyMedia, whereas FitDay put that estimate closer to 53 calories. Even if you go by the higher number provided by BodyMedia, it's still only barely above what I burn per hour just sitting at my desk all day.)

Sorry Jacqui, but this is not a review. Well not by former Ars standards. What does the device measure? How does it get it's "hard data". Probably by magic as it reads over 9000 different elements of your body?Fail.